Implementing simple SSH multi factor authentication.

When an SSH server AuthenticationMethods with multiple methods, like
public key authentions and password, we receive an SSH_PARTIAL_AUTHENTICATION
return code, that was ignored in Remmina.

Now Remmina correctly handle this state and pass to the second mechanism.

More than 2 mechanism are not supported yet, because Remmina doesn't go
behind 3 authentions attempts at the moment (to be fixed).

The next step will be to implement keyboard interactive authentication.

Signed-off-by: Antenore Gatta <antenore@simbiosi.org>

1 files changed, 29 insertions, 15 deletions

diff --git a/src/remmina_ssh_plugin.c b/src/remmina_ssh_plugin.c
index f52e6bbb2..a9213fbcc 100644
--- a/src/remmina_ssh_plugin.c
+++ b/src/remmina_ssh_plugin.c
@@ -267,6 +267,7 @@ remmina_plugin_ssh_main_thread(gpointer data)
 	RemminaSSH *ssh;
 	RemminaSSHShell *shell = NULL;
 	gboolean cont = FALSE;
+	gboolean partial = FALSE;
 	gchar *hostport;
 	gint ret;
 
@@ -309,15 +310,31 @@ remmina_plugin_ssh_main_thread(gpointer data)
 		REMMINA_DEBUG ("tunnel_entrance_host: %s, tunnel_entrance_port: %d", ssh->tunnel_entrance_host, ssh->tunnel_entrance_port);
 
 		while (1) {
-			if (!remmina_ssh_init_session(ssh)) {
-				REMMINA_DEBUG("init session error: %s", ssh->error);
-				remmina_plugin_service->protocol_plugin_set_error(gp, "%s", ssh->error);
-				break;
+			if (!partial) {
+				if (!remmina_ssh_init_session(ssh)) {
+					REMMINA_DEBUG("init session error: %s", ssh->error);
+					remmina_plugin_service->protocol_plugin_set_error(gp, "%s", ssh->error);
+					break;
+				}
 			}
 
 			ret = remmina_ssh_auth_gui(ssh, gp, remminafile);
-			if (ret != REMMINA_SSH_AUTH_SUCCESS) {
-				if(ret == REMMINA_SSH_AUTH_RECONNECT) {
+			switch (ret) {
+				case REMMINA_SSH_AUTH_SUCCESS:
+					REMMINA_DEBUG ("Authentication success");
+					if (!remmina_ssh_shell_open(shell, (RemminaSSHExitFunc)
+								remmina_plugin_service->protocol_plugin_signal_connection_closed, gp)) {
+						remmina_plugin_service->protocol_plugin_set_error(gp, "%s", ssh->error);
+						break;
+					}
+					break;
+				case REMMINA_SSH_AUTH_PARTIAL:
+					REMMINA_DEBUG ("Continue with the next auth method");
+					partial = TRUE;
+					continue;
+					break;
+				case REMMINA_SSH_AUTH_RECONNECT:
+					REMMINA_DEBUG ("Reconnecting...");
 					if (ssh->session) {
 						ssh_disconnect(ssh->session);
 						ssh_free(ssh->session);
@@ -325,18 +342,15 @@ remmina_plugin_ssh_main_thread(gpointer data)
 					}
 					g_free(ssh->callback);
 					continue;
-				}
-
-				if (ret != REMMINA_SSH_AUTH_USERCANCEL)
+					break;
+				case REMMINA_SSH_AUTH_USERCANCEL:
+					REMMINA_DEBUG ("Interrupted by the user");
+					break;
+				default:
+					REMMINA_DEBUG ("Error during the authentication: %s", ssh->error);
 					remmina_plugin_service->protocol_plugin_set_error(gp, "%s", ssh->error);
-				break;
 			}
 
-			if (!remmina_ssh_shell_open(shell, (RemminaSSHExitFunc)
-						    remmina_plugin_service->protocol_plugin_signal_connection_closed, gp)) {
-				remmina_plugin_service->protocol_plugin_set_error(gp, "%s", ssh->error);
-				break;
-			}
 
 			cont = TRUE;
 			break;